Here's my review of the Song Meter. I'll try to get one soon to
comment on the quality of its recordings! Anyone want to help with
the testing?
--oryoki
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Song Meter by Wildlife Acoustics
An autonomous digital audio recorder
Wildlife Acoustics is a small company that produces high tech tools
for naturalists and researchers. The company's products include Song
Scope, a software program that can automatically detect the presence
of a target species in an audio recording. (Attention, seekers of the
Ivory-billed Woodpecker.)
Before target species can be found, however, audio recordings must be
made. To help with this task, Wildlife Acoustics has recently
released an autonomous digital audio recorder called Song Meter.
Efficient use of battery power permits the Song Meter to record,
unattended, on a schedule that lasts several weeks. The recorder
"hibernates" between recording sessions to conserve power.
The Song Meter will record audio samples on the timetable you create.
The timetable is set by specifying the start time and duration. For
example, start at 6:15am and record for 30 minutes. Then wait until
2:00pm and record for 18 minutes and 10 seconds. The Song Meter can
start and stop recording as often as needed. This schedule is
automatically repeated each day.
If a repetitive daily schedule is not sufficient, an advanced schedule
can be set with a simple program. For example, let's say you wish to
record the dawn chorus for two weeks, starting at 4:30am. But the
time of sunrise changes as the calendar advances. After a few days,
you'll miss a lot of the dawn chorus if you wait until 4:30am to start
recording.
Let's assume that the time of sunrise advances 2 minutes and 30
seconds each day as Spring progresses at your latitude. The following
script will adjust the Song Meter's recording schedule accordingly.
- 01 AT TIME 04:30:00
- 02 RECORD 00:45:00
- 03 PAUSE 23:12:30
- 04 GOTO LINE 02 13X
In English, this script says to start recording at 4:30am the first
day, and to record for 45 minutes. To adjust for the change in
sunrise, the recorder is instructed to wait until 4:27:30am the next
day, then record for another 45 minutes. The 13X means repeat 13 more
times, starting 2 minutes and 30 seconds earlier each day for the two
week recording session.
The recording format used by the Song Meter is WAV. The highest
quantization rate is 16 bits per sample, 48,000 samples per second
(often expressed as 16/48). That's the same quality as a DAT
recorder. CD quality (16/44.1) and several slower rates are also
available.
The recorder can capture one channel (mono) or two (stereo). The
preamp gain for each channel can be adjusted separately. To remove
undesirable low frequency noise, a low-cut filter that operates at
approximately 160 Hz is selectable by a switch.
The Song Meter's endurance when running on batteries is impressive.
For example, if you schedule 30 minutes of stereo recording at dawn
and dusk (one hour per day total), the Song Meter will run for 50 days
on its four D size internal cells! An external 5V to 6V DC battery
can be used if longer run times are needed, or if you need to provide
48V phantom power to your mics.
Two SDHC memory card slots are available for file storage. Cards with
Class 4 speed rating are recommended . 16GB memory cards, the largest
available at this writing, are supported. That's a total of 32GB of
file storage capacity. One hour of 16/48 stereo WAV recordings
requires 660 megabytes of storage space, so 32GB can hold
approximately 49 hours of 16/48 recordings. Memory cards of different
capacity (say, a 2GB and a 4GB card) can be used if you wish, as can a
single SDHC card.
The Song Meter is packaged for rugged outdoor use. The recorder has a
rainproof molded plastic outer case. But it's not submersible.
You'll need a larger waterproof container if you plan to use the
recorder under water.
Including its plastic case, the Song Meter measures 8.4 x 7.1 x 2.4 in
(214 x 181 x 61 mm), and weighs 2.8 lb (1270 g), including batteries.
This is close to the size of the Marantz PMD671 and Tascam HD-P2
digital recorders. It must be noted that the Song Meter is not a good
replacement for a general purpose field recorder, primarily because
the Song Meter takes close to 60 seconds to power up and be ready to
record.
The price of the Song Meter starts at $600. There are four versions
of the Song Meter today. To select the model, you must answer two
questions.
First, do you want microphones provided by Wildlife Acoustics and
directly attached to the Song Meter's case? This is the most compact,
least expensive, and perhaps the most weatherproof approach. Or do
you want to use mics attached by cables? You can purchase cable mics
from Wildlife Acoustics, or use you own.
Second, do you want the Song Meter to run from internal batteries?
The internal battery can provide 50+ hours of recording over a period
of many weeks, even months. Or do you prefer to use an external 6V DC
battery, for additional power and battery life? Sealed 6V lead-acid
batteries are inexpensive and readily available.
I'm aware of two competitive autonomous field recorders. The first is
the Froglogger, made by Bedford Technical (www.frogloggers.com). The
second is the Amphibulator, developed by a research team at Western
Kentucky University. These products consist of custom electronics that
control the Marantz PMD660 audio recorder. The electronics, large
external battery and recorder are enclosed in a weatherproof box (a
military ammunition box, in fact).
Both competitors are physically larger and heavier, employ a single
flash memory card (fewer hours of file storage), and use more electric
power (fewer days of usable power from the same size battery) than the
Song Meter. Neither competitor offers as much flexibility in
programming the recording schedule as the Song Meter provides. And
both are more expensive than the Song Meter.
I'm told by a researcher who has used both the Froglogger and
Amphibulator that the Marantz PMD660 has a spotty reliability record
in field use as an unattended recorder. I have no information about
the Song Meter's reliability.
I'm enthusiastic about the Song Meter. Its scheduling flexibility,
battery life, and file storage capacity set new benchmarks for
autonomous recorders in its price range. The combination of the Song
Meter and Song Scope software make a powerful tool for audio
monitoring of wildlife.
For additional information about the Song Meter, see the company web
site, http://www.wildlifeacoustics.com
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